Freezing can be caused by a number of things
as you are having problems just booting up..

I would remove the side of the case and see if the fan on the cpu is operating.If its not Remove it clean it and free up the fan. Also a check on the heatsink associated with the fan.

Also i would reseat the memory chips. make sure you earth your self on to the case before touching the chip sets.

check cmos setting for your hard drive that the correct model is installed.
check all cables power and data cables firmly fitted to the hdd  and cdrom also  the floppy drive

Now remove all cards in the pc except the video card

try for a boot up and go into safe mode hold down F8 or Ctrl key to get into safe mode in win98.  check all the hardware in device manager. Right click/my computer /properties(click)then
click device manager  check all settings for conflicts and multiple setting for cd rom/ monitor/video card and hard drives  remove all of them Thats REMOVE not delete. When you reboot windows will install the correct drivers for devices installed..

john..

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